1. Field of the Invention
This invention relates to a device for recording indicia on paper or similar media.
2. Description of the Prior Art
Paper or similar media which has a large reflection coefficient or a large transparency or both with respect to light and which has a surface which changes in color under the action of heat is well known. Such papers may change color or transparency as a result of the application of a light source or of a heat source.
It has become necessary, in recent years, to increase the speed with which indicia, such as alpha-numeric indicia may be placed upon a record carrier, such as paper. Fast electronic data processing systems require data print-out systems capable of operating at extremely high speed. The inertia of moving parts in mechanical devices limits the recording speeds which can be achieved. In the past, these limits could be overcome only by extremely complex constructions involving extremely high cost.
After the invention of the laser, devices for the printing of indicia by means of a light source of a high intensity were developed. In such devices, the light beam may be shaped to the selected alpha-numeric character and thereafter be directed to act upon color particles located in a color carrier. Such devices include the use of color carriers which are positioned immediately adjacent to the recording media or paper. When a light source is directed at preselected portions of the color carrier, the color particles are transmitted, by way of vaporization, onto the recording carrier or paper. (see, for example, German Auslegeschrift No. 1,957,126).
Devices of this character have the advantage of relative fast and quiet operation due to the elimination of mechanical elements required by the previously known printing devices. However, on the other hand, due to the necessity of maintaining the interposed color carrier, the printing speed is limited by the maximum feed speeds obtainable with the color carrier. Additionally, a moving color carrier requires very intensive maintenance which reduces the overall reliability of the printing device. Thus, for example, special warning devices are necessary to indicate, on the one hand, the end of the color carrier strip or sheet, and on the other hand, to interrupt the writing operation during the exchange or replacement of the color carrier.